The Emperor Penguin, Aptenodytes forsteri, is the largest penguin. Penguins are birds that cannot fly, but penguins swim very well and spend most of their lives in the sea.

Habitat: The Emperor Penguin lives in colonies on pack ice in Antarctica. It is kept warm in the harsh environment by a thick layer of blubber (fat) and by insulating down (feathers).

Feathers: Penguins have shiny, waterproof feathers that help keep their skin dry. They have more feathers than most other birds - about 70 feathers per square inch. Each year, penguins molt, losing their old feathers and growing new ones.

Anatomy: The Emperor Penguin is up to 3.7 feet (1.1 m) tall and weighs up to 65 pounds (30 kg); this about half the size of an adult person. Males and females look very similar. Like all penguins, Emperor Penguins have a big head, a short, thick neck, a streamlined shape, a short, wedge-shaped tail, and tiny, flipper-like wings. They have webbed feet which they use for swimming. Penguins are countershaded; they have a lighter color on the belly and a darker color on their back; this coloration helps camouflage them when they are in the water, hiding them from predators.

Diet: Emperor Penguins are carnivores (meat-eaters) who hunt in the sea. They eat fish and squid.

Reproduction: After the female lays a single egg, she goes off to sea. The male incubates the egg, keeping it warm on his feet, enveloped by the stomach, in a "brood pouch" for 72 days (during the coldest part of the Antarctic year). He feeds his chick with "milk" produced by a gland in his esophagus; during this time, he loses half his body weight.